<?php
function brilliant_gallery_help($path, $arg) {

  $output = '';

  switch ($section) {
    case "admin/help#brilliant_gallery":
      $output = '<p>'. t("Highly customizable Drupal module creating a table gallery of quality-scaled images from any number of folders.") .'</p>';
      break;
  }

  return $output;
}
?>

$section should be $path?